1. Field of the Invention
The present invention relates to an apparatus for attaching a top end stop to an end of a row of coupling elements of a slide fastener stringer.
2. Prior Art
A top end stop having a U-shaped or Y-shaped cross section including a pair of opposed spaced legs is attached to a longitudinal edge of a slide fastener stringer tape by putting the tape edge between the spaced legs and deforming or clinching the legs toward each other over the tape edge by a pair of relatively movable punches. In applying the top end stop, it is necessary to supply it correctly between the punches and to press the punches toward each other while the top end stop is being maintained stably between the punches against any displacement.
One of the prior proposals to meet the above requirements is disclosed in Japanese Patent Publication No. 39-4425 which shows an apparatus for automatically supplying a top end stop between a pair of opposed bunches and clinging the top end stop over the longitudinal edge of a stringer tape that has been inserted between the opposed legs of the top end stop. The prior device comprises a drive cylinder having a first punch and a driven tubular cylinder fitted over the drive cylinder and having a second punch, the first and second punches being supplied with an end stop therebetween. With the end stop supported between the punches, the drive and driven cylinders are turned about their axes through a predetermined degree to a clinching position, at which a longitudinal edge of a stringer tape is inserted between the legs of the end stop. Then the drive cylinder is actuated to cause the first punch to move toward the second punch on the driven cylinder as it is held at rest, thereby clinching the legs of the end stop over the longitudinal tape edge.
The problem with the known device is that a relatively large end stop cannot be attached properly because the first punch moves along an arcuate path about the axis of the drive cylinder, and fails to apply uniform clinching forces over the entire area of the legs of the end stop.